A prodrug of the capsid assembly modulator improved druggability and lowing HBsAg and HBeAg for the treatment of chronic hepatitis B

Structural optimization of phthalazine derivatives for anti-HBV activities to improve oral bioavailability

The hepatitis B virus (HBV) capsid protein forms a protective nucleocapsid essential for viral replication, establishing capsid assembly modulation as a promising therapeutic strategy. Based on previous mechanistic studies, we identified phthalazine derivatives as potent HBV capsid assembly modulators (CAMs), with Yhhu6517 exhibiting submicromolar antiviral activity in vitro. However, its clinical translation was hindered by poor oral pharmacokinetics (PK), due to rapid first-pass metabolism of oxidation-prone primary alcohol groups. Through metabolic stability-guided structure-activity relationship (SAR) studies involving systematic replacement of primary alcohols with non-primary alcohol-derived hydrophilic groups, we optimized the fragments to yield compound 2p. This optimized candidate 2p maintained a potent anti-HBV activity (IC50 = 0.016 μM in HepG2.2.15 cells) while demonstrating improved an oral bioavailability (F = 80.6 % in mice) and enhanced plasma exposure (AUC0-24h = 10.3 μg·h/mL). These findings confirm phthalazine-based anti-HBV agents, with compound 2p emerging as a candidate for the further development.

A patent review of hepatitis B virus core protein allosteric modulators (2019-present)

INTRODUCTION

The hepatitis B virus (HBV) core protein is a significant therapeutic target due to its essential role in HBV replication. Over the past five years, numerous structurally unique CpAMs have been patented. However, no compounds have been approved due to various issues such as poor pharmacokinetics (PK) and hepatotoxicity. As a result, there is an urgent need to develop novel CpAMs without these limitations.

AREAS COVERED

This review provides a comprehensive analysis of patents related to CpAMs from 2019 to the present, with the aim of delineating the chemical evolution that has occurred in the pursuit of more promising CpAMs. The sources of patent information included databases of the European Patent Office, the China Patent Office and the U.S.A. Patent Office, while relevant research articles were accessed through PubMed.

EXPERT OPINION

During the optimization of CpAMs, striking a good balance between activity and druggability usually poses a certain challenge while the emergence of drug resistance issues further complicates the development process. A comprehensive analysis of the structural features of CpAMs and identification of essential patterns in chemical evolution can reveal common principles that improve pharmacodynamic (PD) and PK profiles, thereby facilitating the discovery of next-generation CpAMs.

Computer-aided drug repurposing & discovery for Hepatitis B capsid protein

The primary objective of this study is to harness computer-aided drug repurposing (CADR) techniques to identify existing FDA-approved drugs that can potentially disrupt the assembly of the Hepatitis B Virus (HBV) core protein (HBcAg), an essential process in the virus's life cycle. By targeting this critical step, our study aims to expand the repertoire of therapeutic options for managing chronic Hepatitis B infection, a major global health challenge. Utilizing a combination of computational methods, including the CavityPlus server for ability to analyze druggable protein cavities and extract pharmacophore features and LigandScout for pharmacophore-based virtual screening of a vast library of FDA-approved drugs was conducted. Molecular dynamic simulation (MDS) was employed to evaluate the stability of HBcAg, complexed with Heteroaryldihydropyrimidine (HAP) and statins exhibiting particularly strong binding energies and conformational compatibility. Our approach focused on identifying pharmacophore features that align with known HBcAg inhibitors. The study identified several promising candidates, including Ciclopirox olamine, Voriconazole, Enasidenib, and statins, demonstrating potential interactions with HBc protein residues. Molecular docking further validated these interactions. The significance of these findings lies in their potential to offer new, effective therapeutic strategies for HBV treatment, particularly as alternatives to current therapies that often suffer from issues of viral resistance and adverse side effects. MDS analysis verified the robustness of HAP and statins by showing a high level of binding energies and compatibility with HBcAg. Our results provide a foundation for further experimental validation and underscore the utility of computer-aided drug repurposing as a rapid, cost-effective approach to drug discovery in antiviral research. This study contributes to our understanding of HBV biology and opens avenues for developing novel anti-HBV therapies based on repurposed drugs. The highlighted compound may also enhance the challenges of drug resistance when used as a combination therapy.

Classifying hepatitis B therapies with insights from covalently closed circular DNA dynamics

The achievement of a functional cure for chronic hepatitis B (CHB) remains limited to a minority of patients treated with currently approved drugs. The primary objective in developing new anti-HBV drugs is to enhance the functional cure rates for CHB. A critical prerequisite for the functional cure of CHB is a substantial reduction, or even eradication of covalently closed circular DNA (cccDNA). Within this context, the changes in cccDNA levels during treatment become as a pivotal concern. We have previously analyzed the factors influencing cccDNA dynamics and introduced a preliminary classification of hepatitis B treatment strategies based on these dynamics. In this review, we employ a systems thinking perspective to elucidate the fundamental aspects of the HBV replication cycle and to rationalize the classification of treatment strategies according to their impact on the dynamic equilibrium of cccDNA. Building upon this foundation, we categorize current anti-HBV strategies into two distinct groups and advocate for their combined use to significantly reduce cccDNA levels within a well-defined timeframe.